This invention relates to package and article carriers and particularly to reusable carriers that are adapted to carry paper bags.
In general there are many devices known which can be permanently adhesively fixed to a sack or paper bag in order to make it more convenient for a shopper to carry such packages home. Those devices typically adhere to the paper over a relatively large surface area and are therefore able to distribute the large stresses produced when for example a bag is full of groceries. Some very familiar detachable devices engage strings that encircle the package to be carried and through the agency of the strings distribute the stress to the sides and bottom of the parcel. See for example U.S. Pat. No. 824,904.
In order to provide a paper bag carrier of moderate size one is confronted by the substantial stresses that will be produced in the immediate vicinity of the carrier. This problem is further complicated by the fact that any irregularity or roughness used to retain the paper from slipping provides points or lines at which stresses concentrate. Such points or lines induce fractures in the paper which can propagate a rip along the paper. It was not known in the prior art how to adapt a device to contain the paper fractures before they could propagate out of the region of support provided by the carrier.
Furthermore, the prior art is characterized by mechanically complex gripping apparatus for the carrying of planar materials. For example, U.S. Pat. Nos. 3,653,708 and 3,780,923 employ difficult to manufacture counterrotating rollers retained in movable axles between converging support members; U.S. Pat. No. 1,121,130 employs a running gear retained in a sliding bracket within converging support members; U.S. Pat. No. 489,782 employs a double excentrically pivoted and serrated wheel. Each of those prior art apparatus is further distinguished by the fact that the surfaces which actually bear on the materials to be carried are small in area. This limitation is believed to have been necessary in the prior art due to the tendency of apparatus which has large material retaining surfaces to jam and to be difficult to disengage after the material has been transported.
The limitation to small contact surface areas makes unsuited for paper bag carriers such devices as exist in the prior art for retaining rods or wires, such as for example as disclosed in U.S. Pat. Nos. 801,377; 3,576,057 or 2,106,373.
The prior art is further characterized by heavy unwieldy construction unsuitable for carriers that could be used by a supermarket patron or carried conveniently in a pocket or purse when not in use.